Short answers, pulled from the story.
The Wall of Sound is a recording technique developed by Phil Spector that used large groups of session musicians playing in unison, combined with heavy reverb and echo effects, to create a densely layered orchestral pop texture. Spector described his records as "little symphonies for the kids" and worked primarily at Gold Star Studios in Hollywood with arranger Jack Nitzsche and engineer Larry Levine.
Phil Spector produced five number-one singles on the Billboard Hot 100, including "To Know Him Is to Love Him" by the Teddy Bears (1958), "He's a Rebel" by the Crystals (1962), "You've Lost That Lovin' Feelin'" by the Righteous Brothers (1965), "The Long and Winding Road" by the Beatles (1970), and "My Sweet Lord" by George Harrison (1970). He produced a total of 19 top-ten singles between 1958 and 1971.
Phil Spector was convicted of second-degree murder for the death of actress Lana Clarkson, who was shot in the mouth at his mansion in Alhambra, California, on the 3rd of February 2003. After a mistrial in 2007, a retrial jury returned a guilty verdict on the 13th of April 2009, and he was sentenced on the 29th of May 2009 to 19 years to life in prison.
Allen Klein, the Beatles' new manager, brought Spector to England in early 1970. After Spector produced John Lennon's solo single "Instant Karma!," which reached number 3, Lennon and George Harrison invited him to edit the abandoned Let It Be sessions into a releasable album. He went on to co-produce Harrison's All Things Must Pass and Lennon's Imagine, as well as serving briefly as head of A&R at the Beatles' Apple Records.
Phil Spector was inducted into the Rock and Roll Hall of Fame in 1989, inducted by Tina Turner. He was also inducted into the Songwriters Hall of Fame in 1997 and received the Grammy Trustees Award in 2000. In 2004, Rolling Stone ranked him number 63 on its list of the greatest artists in history.
Phil Spector died on the 16th of January 2021 at the age of 81 while incarcerated at an outside hospital. He had been diagnosed with COVID-19 in December 2020, was taken to San Joaquin General Hospital in French Camp, California, on the 31st of December, and was intubated the following month. His daughter Nicole attributed the cause of death to complications of COVID-19.